Support doesn't break off clean...

[Dukinfed]

what am I doing wrong?

Simplify 3d default setting except for the following:
First Layer Height: 200%
First Layer Speed: 25%

Outline Underspeed: 80%

Extruder temp: 215 Bed: 70

Test Sphere top


Test Sphere bot

[jimc]

thats the typical underside of a steep overhang on fdm printers. it has nothing to do with the m2 or s3d. all printers will print this similar. the underside of a sphere is especially difficult. remember that there is usually a one layer gap between the top of the support and the bottom of you object. this makes it a little sloppy. if that gap was not there then you could never remove the support from the model. the best thing you can do if you need a decent underside is just increase the support fill percentage.

[ednisley]

what am I doing wrong?

Probably nothing much: supported undersides are like that and that's the way they are.

You can get a perfect sphere (well, as perfect as a consumer-grade 3D printer will allow) by splitting it along the equator, printing both hemispheres flat side down, then gluing them together. If you add alignment pin holes, they'll fit exactly and you might not even notice the seam.

This isn't quite a sphere, but it'll give you the idea:

http://softsolder.com/2011/10/15/thing- ... der-thing/

A better alignment pin hole with a glue gutter:

http://softsolder.com/2013/11/12/improv ... 3d-prints/

Use something hellish like Weld-on IPS 4 containing methylene chloride for a perfect bond.